The invention relates to improved apparatus for linearly moving a massive core into and out of a shell, and is primarily designed for the extracting and reinsertion of heat exchanger tube bundles from and into heat exchanger shells in chemical processing plants. An exemplary prior art apparatus for effectively performing the tube bundle extraction and reinsertion functions is described in copending Application Ser. No. 923,443 filed July 10, 1978, now U.S. Pat. No. 4,227,854, the disclosure of which is hereby incorporated by reference herein. While the structure disclosed therein as well as other removal structures (such as shown in U.S. Pat. No. 4,053,062) have been acceptable for performing their intended functions, there have been some drawbacks associated therewith.
Some prior art structures are difficult to properly balance during tube bundle removal, and it is important that such balancing be accomplished in as simple and effective a manner as possible in order to insure quick and effective removal of the core without damage to the tube bundles. Additionally, there have been safety problems associated with some prior art structures since an operator must stay with the structure during the removal operations in order to control the functioning thereof, and the operator can be vulnerable under some circumstances in such a position. Additionally, other prior art structures have been somewhat limited in being able to properly position the core for quick and effective reinsertion into the shell, have had shell clamping structures that did not readily adapt to differently sized cores and shells with which the apparatus might be utilized, and have not been adapted for gradual--rather than abrupt--release of the removal structure from the heat exchanger shell after a core withdrawal.
According to the present invention, apparatus is provided which overcomes many of the drawbacks inherent in prior art structures, and in general provides a core extraction device which is properly positionable, is easily safely operated, and can perform the extraction and reinsertion functions with a great deal of precision in a relatively short period of time. The apparatus according to the invention is also adaptable for use in a total core maintenance system so that the removed core can be properly handled without ever attaching a sling to the core, thus minimizing the chances for damage to the tube bundles.
The apparatus according to the present invention basically comprises an elongated frame structure including a first pair of parallel beams, means for connecting and locking the frame structure to the shell, a moveable carriage operatively mounted for movement along and with respect to the spaced first beams toward and away from the shell, the carriage having means for interconnection to the core, means operatively associated with the carriage for exerting a force thereon for moving it toward and away from the shell, and a plurality of thrust surfaces associated with the frame structure for cooperating with the force exerting means. The force exerting means and the thrust surfaces may be identical to those disclosed in copending Application Ser. No. 923,443.
One improved aspect of the apparatus according to the present invention is the provision of balance control means operatively mounted on the frame structure for taking into account changes in the location of the center of gravity of the apparatus-core combination during removal or insertion, and during supporting of the core removed from the shell, the balance control means comprising a plurality of members mounted on spaced portions of the frame structure; means for mounting the members on the frame structure for movement toward and away from the center of gravity of the frame structure; and powered means for effecting movement of the members toward and away from the center of gravity of the frame structure. Preferably, the members include four arms, one disposed at each corner of the frame structure, and the mounting means comprise pivot means for mounting each of the arms for pivotal movement about an axis perpendicular to the direction of elongation of the frame structure. The powered means preferably comprise a fluid actuated piston and cylinder assembly for each arm mounted at one end thereof to the elongated frame structure and the other end thereof to the arm for moving the arm about the pivot means. Each of the arms receives a cable from a crane, the cables in turn being connected to a beam which in turn is connected by a pair of cables to a single crane hook. No portion of the frame structure extends above the first parallel beams, and the carriage is moveable along the parallel beams in a direction coincident with the central axis of the core, and the arms are mounted on the frame structure below the first beams.
According to another improved aspect of the apparatus according to the present invention, the means for connecting and locking the elongated frame structure to the shell comprises a pair of side arms, each located opposite the other on opposite sides of the elongated frame structure at substantially the central axis of the core. The side arms are operatively mounted to the frame structure for pivotal movement about an axis perpendicular to the direction of movement of the carriage and power means are provided for pivoting the side arms about these axes. A stationary clamp element is formed on each of the side arms, and a moveable clamp element is pivotally mounted to each of the side arms for movement about an axis parallel to the side arm axes, further power means being provided being mounted on each of the side arms associated with each of the moveable clamp elements for pivoting the elements about their axes. Such apparatus further includes attitude sling means including a powered linear force application device mounted on a support arm associated and pivotal with each of the side arms.
The apparatus according to the present invention also includes control means for all the power means associated therewith, the control means including a control console, and means for detachably mounting the control console to the frame structure. An umbilical extends from the control console to the power means, the umbilical having sufficient length to allow the control console to be mounted in a position safely spaced from the frame structure during utilization of the apparatus for moving a massive core. The power means preferably comprise hydraulic cylinder assemblies and include at least one hydraulic pump for providing hydraulic fluid under pressure for powering the hydraulic cylinder assemblies. The apparatus further comprises a pneumatic pilot control system for controlling operation of the hydraulic cylinder assemblies, the pneumatic control system including a pneumatic motor for powering the hydraulic pump and control means including pneumatic valves and manual actuators therefor, the actuators being mounted on the control console.
According to another aspect of the present invention, the elongated frame structure also includes a second pair of parallel beams disposed below the first pair of beams, and a plurality of trolleys mounted for guided movement along and with respect to the second pair of parallel beams. Each of the trolleys comprises a body portion, a pair of individually adjustable leaves, the leaves being pivotally mounted to the body portion, actuator means for individually pivoting each of the leaves about its pivotal mounting to move a portion thereof toward and away from the body, and a plurality of wheels mounting the body for rolling movement along the second parallel beams. The beams preferably comprise channels for receiving the wheels along three sides thereof and have readily removeable means for blocking movement of the wheels out of the front ends of the channels, and the plurality of wheels comprises two spaced sets of wheels. The body has no portion thereof extending below the wheels, and the frame structure comprises no components interfering with movement of the wheels out of the front ends of the second beams when the blocking means are removed.
It is the primary object of the present invention to provide improved apparatus for linearly moving a massive core into and out of a shell. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.